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Race/IQ: A Coda on Mexican-American IQ

Although the claims regarding Irish IQ had unexpectedly attracted so many of the angry attacks on my recent Race/IQ series, it seemed quite obvious to me that this represented merely a stalking-horse for the related question of Mexican IQ. In my original article, I had pointed out that up to the early 1970s, both Mexicans and Ireland […]

Although the claims regarding Irish IQ had unexpectedly attracted so many of the angry attacks on my recent Race/IQ series, it seemed quite obvious to me that this represented merely a stalking-horse for the related question of Mexican IQ.

In my original article, I had pointed out that up to the early 1970s, both Mexicans and Ireland Irish had identically low IQs, and perhaps coincidentally both were impoverished, heavily rural populations. However, in the decades which followed, Ireland had grown more affluent and urbanized, and Irish IQ had rapidly risen, eventually reaching a value almost identical to that of the neighboring British. I then noted the bits of evidence that the IQ of American-born Mexican-Americans had also apparently been rising at a similarly rapid pace, perhaps propelled by similar gains in socio-economic and urbanization factors. Since massive recent immigration has rendered the data on the Mexican-American portion of this analogy somewhat fragmentary and inconclusive, my critics naturally focused their most intensive fire on the Irish side, denying any large change in the local IQ; but an exceptionally strong correlation of 0.86 seems now to have decisively resolved this dispute in my favor.

In the most recent iteration of this debate, I mentioned that Hans Eysenck, one of the leading psychometricians of the 20th century, had apparently discussed the well-known facts of low Irish IQ in his 1971 book Race, Intelligence, and Education.  Although the quotes I found seemed quite reliable, I decided to confirm them for myself, and for $6.40 (plus $3.99 shipping and handling) ordered his book from Amazon. When the copy arrived, I was disappointed to discover it contained no index, so I just began browsing through the contents to find the Irish references.

These were indeed exactly as had been claimed. Citing older research studies not mentioned in more recent texts, Eysenck described the Irish/British IQ gap as being almost identical in size to the black/white IQ gap in America, and provided several half-plausible explanations of why the Irish might have become an innately low intelligence population (pp. 127-128). The entire discussion ran merely a page or two, but given Eysenck’s stature in the field it undoubtedly represented the conventional academic wisdom of his day.


However, in skimming the book in search of those references, I discovered several far more interesting and surprising items.

First, Eysenck casually mentioned the fact that Americans of Greek, Italian, Spanish, and Portuguese ancestry had very low IQs compared to their separated European cousins, and suggested that this was because the least intelligent members of those ethnic groups had immigrated to America (p. 47-48).  Yet just forty years later, that pattern has completely reversed itself, with the children or grandchildren of those same American ethnicities now having far higher IQs than their stay-at-home European relatives. So these days, the explanatory “Just So Story” has switched polarity, and we are asked to assume that it was only the brightest Greeks and South Italians who took ship for the New World.  Explanatory arguments which reverse themselves every generation or two hardly acquire great credibility in the process.

But even more remarkable was Eysenck’s long and detailed discussion of Mexican-American IQ (pp. 120-127). Although he mentioned that the scores themselves were well below those of white schoolchildren, he explained that a close examination of the pattern of the results across different types of tests and circumstances indicated that this particular gap was very likely due to factors of socio-economic or cultural deprivation, perhaps magnified by language problems, and that the underlying intelligence of Mexicans was probably pretty close to that of whites. Therefore, he predicted that the Mexican IQ would converge to the white value as social conditions improved, which was exactly what my fragmentary evidence seemed to indicate.

Worse still for my critics, Eysenck’s discussion had been drawn directly from the work of Arthur Jensen, who had conducted detailed research studies on the question of Mexican-American intelligence and had similarly concluded that the IQ gap with whites was overwhelmingly “environmental” in origin. Now I claim no great expertise in IQ matters, but those who do seem to regard Jensen as one of the most towering figures in the history of their academic discipline.

Presumably, this might place my numerous and noisy IQ-activist critics in a bit of a quandary. My strong impression is that Jensen and Eysenck rank as perhaps the Marx and Engels of their movement, and suddenly purging them both on charges of Gouldist-deviationism would surely constitute an ideological earthquake, vastly greater in magnitude than that of the Moscow Purge Trials or Khrushchev’s 1956 “Secret Speech” on Stalin. Yet for my critics to admit they’d never bothered consulting the past pronouncements of their intellectual idols might also be quite embarrassing.

Naturally, such difficulties are non-existent for those individuals whose overweening self-confidence leads them to lob endless casual insults all across the Internet while regarding the evidence of their anecdotal personal experiences in New Mexico as vastly superior to my quantitative analysis or perhaps even the detailed IQ research of Prof. Arthur Jensen.

Lastly, this once again demonstrates the enormous potential value of occasionally examining the contents of old books and articles, as opposed to simply relying upon the echo-chamber effect of reading columns produced by ideological websites or bloggers, most of which tend to quote each other back and forth, often with diminishing reference to external reality.


And on a totally unrelated matter, the Wall Street Journal just ran a major article on the difficulties of teaching students from a non-English speaking family background, and the various suggestions of educational experts for improving this process. Although the article was quite detailed, I noticed the total absence of a certain two word phrase, which surely would have been central to any such discussion just a dozen or more years ago. Ironically enough, I suspect that the younger readers of this column don’t have the faintest idea of what I mean.

(cross-posted at www.ronunz.org)



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